Summary of Common Conditions Seen in OSCEs
Causes of PUO can be divided into:
- Infection
- Malignancy
- Inflammatory/rheumatological diseases
- Miscellaneous
- Unknown
Infections (25%)
| Condition | Key points |
| Tuberculosis | Cough Night sweats (drenched) Haemoptysis Weight loss Tuberculosis contact South Asian |
| Abscess | Spiking fever Temperature chart looks like a zig-zag line |
| Endocarditis | New murmur and fever Weight loss Anaemia Embolic phenomena (stroke) Janeway lesions Osler’s nodes Splenomegaly Prosthetic valve Intravenous drug use Requires blood cultures and transoesophageal echocardiogram |
| Osteomyelitis | Pain, tenderness Swelling Heat |
| Pneumonia | Elderly Alcohol Previous tuberculosis Smoking Immunosuppression |
| Urinary tract infection | Frequency Dysuria Haematuria |
| Intracerebral – meningitis, encephalitis, abscess | Delirium Cognitive ± neurological features Lumbar puncture CT brain |
| HIV | Non-specific symptoms Opportunistic infections Endemic area Risk factors |
| Hepatitis | Abdominal pain Jaundice Alcohol Obesity Intravenous drug user |
| Tropical infections | Foreign travel Malaria prophylaxis (compliance) Immunisation history Consider the wider public health aspect also (contacting the CCDC, notifiable diseases) |
Neoplasms (20%)
| Condition | Key points |
| Lymphoma | Tiredness Lymphadenopathy Night sweats Pruritus Weight loss |
| Leukaemia | Bruising Infections Anaemia |
Connective Tissue Disease (20%)
| Condition | Key points |
| Rheumatoid arthritis | Symmetrical Swollen Painful Small joints of hands (metacarpophalangeal, proximal interphalangeal) |
| Systemic lupus erythematosus | Non-specific symptoms (malaise, tiredness) Weight loss Alopecia Malar rash Photosensitivity Mouth ulcers Arthralgia Young women |
| Giant cell arteritis | Elderly Associated with polymyalgia rheumatica Headache Temporal tenderness Jaw claudication Amaurosis fugax |
| Polymyalgia rheumatica | Morning stiffness in the proximal limb muscles Tiredness Anorexia Weight loss |
| Still’s disease | Joint pain and swelling Salmon pink skin rash Fever peaks in afternoon |
Miscellaneous (15%)
| Condition | Key points |
| Drug fever (3%) | Beta-lactam antibiotics (penicillin) Isoniazid Sulphonamide (sulphasalazine) |
| Pulmonary embolism | Shortness of breath Chest pain Haemoptysis Recent surgery, immobility |
| Inflammatory bowel disease | Abdominal pain Weight loss Diarrhoea (ulcerative colitis – bloody) |
Occupation-Associated Illness
| Occupation | Condition |
| Sewage worker | Leptospirosis |
| Farm worker | Zoonosis |
| Healthcare worker | Hepatitis, HIV |
| Forestry worker | Lyme disease |
| Abattoir workers | Q fever (Coxiella burnetii) |
Remember that 25% of patients with a PUO never receive a diagnosis for why it has occurred.
Hints and Tips for the Exam
Definition of PUO
The definition of PUO is a temperature over 38.3°C for longer than 3 weeks with no obvious source despite investigation.
Devising a List of Differential Diagnoses
PUO has a vast differential diagnosis so approaching this station can be tricky. Cast your net wide. Only home in on a possible diagnosis after you have asked all the key questions (i.e. even if it is clear that a connective tissue disorder is the cause, do not forget the travel and sexual histories). There is a lot to cover so be succinct, but give the patient enough time to respond so that you can gain the most marks.
In this station, one of your goals is to differentiate between whether the patient should be admitted for further investigation or can be monitored and treated in the community.
Structure your questioning according to different body systems. This will ensure you do not miss anything obvious.
Asking for the patient’s personal thoughts on the cause is imperative and more often than not gives the diagnosis away in this station. This should also be used as an opportunity to allay the patient’s fears if the diagnosis is clear.
In cases of PUO, the history and examination should be repeated at intervals to see if further information can be gleaned to achieve a diagnosis. This should be mentioned to the examiner when you present the case.
Examining Patients with PUO
Examining a patient with a PUO involves a thorough examination focusing on possible causes that were highlighted within the history. Pay particular attention to the patient’s skin, mucous membranes and lymphatic system, and the presence of abdominal masses.
Key Investigations for Patients with PUO
Be prepared with a number of investigations at the PUO station. Be able to justify each test based on your history, examination findings and likely differential diagnosis:
- Bedside tests: measure the temperature!
- Full blood count, white cell count and differential, Us+Es, C-reactive protein, liver function tests, ESR, blood film, amylase
- Blood cultures (×3, taken at different times from different sites using an aseptic technique.)
- Urine microscopy, culture and sensitivity
- Swabs (throat, ear, penile, high vaginal/endocervical)
- Autoantibody screen – antinuclear antibody, ANCA, rheumatoid factor
- HIV test, PPD, interferon-gamma release assay for TB
- Chest X-ray
- Abdominal ultrasound scan
- CT/MRI – the site will be dictated by what you find from your history and examination
In your management plan, first decide whether the patient needs to be admitted. A multidisciplinary approach is key in PUO (as with every OSCE).
Questions You Could Be Asked
Q. What are the common symptoms of tuberculosis?
Q. What initial investigations would you consider in a patient presenting with a PUO?
A. The answers can be found in the chapter text.
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